The present invention relates generally to air handling systems. More particularly, the present invention relates to an economizer.
Air handling systems are widely used to condition and distribute air within an internal space such as a commercial building. FIG. 1 shows a cross-section view of a conventional air handling system 10 mounted on a roof 12 having as a component an economizer 14 positioned upstream of air handling unit components 22. By way of example, the air handling unit components 22 may include components such as a cooling coil, a heating coil, and/or a fan, all of which are costly to operate.
Generally, the economizer 14 consists of a return air vent 18 in communication with an internal space 20, an outside air vent 22 in communication with the outside environment 24, and a mixing chamber 26. The return air vent 18 is in communication with the mixing chamber 26 by two straight dampers 28 which open and close thru a maximum angular rotation of 45 degrees to control the flow of return air into the mixing chamber 26. Similarly, the outside air vent 22 is in communication with the mixing chamber 26 by two straight dampers 30 which open and close to control the flow of outside air to the mixing chamber 26. Depending upon one or more the characteristics of the outside air (i.e, temperature, humidity, etc.) and desired characteristics of the supply air, the straight dampers 28 and 30 are synchronously moved by a control mechanism moved (not shown) to provide an optimum mixture of return air and outside air in the mixing chamber 20 which minimizes the operation of the air handling unit components 22 and the energy costs incurred therewith.
Conventional economizers of the type exemplified by FIG. 1 have several drawbacks. Movement and final position of the straight dampers 28 cause an excessive pressure drop across the straight damper 28, thereby increasing the amount of energy needed to operate the second stage conditioning system 16 and/or the air handling system 10.
One object of the present invention is to provide an economizer that has a significantly lower pressure drop across the return air vent when mixing return air and outside air.
The present invention is an economizer that can mix outside air and return air while incurring a significantly low pressure drop across the return air damper than conventional devices. In one embodiment, the economizer comprises a mixing chamber, a return air vent, and an outside air vent. The economizer further comprises a plurality of curved return air dampers moveable from an open position to a closed position to control the flow of return air to the mixing chamber. The economizer further comprises a plurality of straight dampers moveable from an open position to a closed position to control the flow of outside air to the mixing chamber. During operation of the economizer, a significantly lower pressure drop exists across the curved return air dampers than in conventional economizers. When used in connection with commercial buildings, for example, the economizer of the present invention significantly reduces energy consumption associated with the operation of the overall air handing system which results in significant cost savings to the commercial customer.